1. Field of the Invention
This invention relates to aryl and heteroaryl fused aminoalkylimidazole derivatives which, when appropriately substituted, are selective modulators of Bradykinin B2 receptors. This invention also relates to pharmaceutical compositions comprising such compounds. It further relates to the use of such compounds in treating a variety of central and peripheral disorders. Additionally, compounds of this invention are useful as positive controls in assays for BK-2 receptor activity and when appropriately labeled as probes for the localization of BK-2 receptors in tissue sections.
2. Background
Bradykinin (BK), a nonapeptide, and the closely related decapeptide kallidin (Lys-BK), are produced by proteolytic cleavage of high molecular weight kininogen by plasma kallikreins (Bhoola et al., Pharmacol. Rev. 1992, 1-80; Regoli et al. Pharmacol. Rev. 1980 1-46; Bathon and Proud, Ann. Rev. Pharmac. Toxic. 1991, 129-162). The effects of bradykinin and kallidin are mediated by specific seven transmembrane G-proteirn coupled receptors.
The existence of two bradykinin receptor subtypes was initially proposed by Regoli and Barabe (Pharmacol. Rev., 1980, 1-46) and this hypothesis had been unequivocally confirmed within the last six years. The expression and cloning of a rat bradykinin receptor, now known to be a BK-2 receptor, was first reported by McEachern et al. (PNAS 1991, 88(17):7724-7728). Hess, et al. (Biochem Biophys. Res. Commun. 1992, 260-268) reported the cloning and pharmacological characterization of a human BK-2 receptor. Menke, et al. (J. Biol. Chem. 1994, 21583-21586) describes the expression and cloning of a human bradykinin (B1) receptor.
Both BK and kallidin activate the B2 receptor while only kallidin is active at the B1 receptor. However, both compounds are rapidly cleaved to produce B1 receptor agonists, and then further degraded by kinases to produce inactive peptides. The instability of BK and kallidin suggests that these peptides act. locally. Both receptors are expressed in a number of peripheral tissues as well as in the CNS.
The B2 receptor is expressed constitutively in a variety of: tissues (Regoli et al., Eur. J. Pharmacol., 1981, 105-115) and accounts for the majority of the acute pharmacological effects of bradykinin. The B1 receptor is inducibly expressed (Regoli et al., Eur. J. Pharmacol., 1981, 105-115; Deblois et al., Immunopharmacology, 1989, 187-98; Marceau, Immunopharmacology, 1995, 1-26.) and appears to act predominantly in, pathophysiological conditions (Dray and Perkins, J. Neurophysiol., 1993, 256-272). The BK-1 receptor has been especially implicated in persistent hyperalgesia and chronic inflammation.
Bradykinin is an effector of a number of inflammatory responses including bronchoconstriction, plasma extravasation, release of prostaglandins/leukotrienes, smooth muscle contraction/relaxation and nociception (Burch et al., Med. Res. Rev. 1990, 237-269). Bradykinin and the related peptide kallidin have been implicated in a number of disease conditions, including but not limited to pain (Whalley et al., Naunyn. Schmiedeberg""s Arch. Pharmc., 1987, 652-655), rhinitis, anaphylaxis, inflammatory bowel disease, vascular permeability (Schachter et al., Br. J. Pharmac., 1987, 851-855; Whalley et al., Naunyn Schmiedeberg""s Arch. Pharmc., 1987, 430-433), algesia, vasodilataion, inflammatory response (Burch and De Haas, Naunyn Schmiedeberg""s Arch. Pharmc. 1990, 189-193), hypotension associated with sepsis (Sharma et al., Agents Actions, 1992, 258-269), bronchopulmonary disorders including asthma (Jin et al., Br. J. Pharmac., 1989, 598-602), and increased cell proliferation. Antagonists of the BK-2 receptor are useful in treating these conditions. Additionally bradykinin has been implicated in increased glucose uptake, and decreased blood glucose concentration (Henriksen et al., Diabetes, 1996, S125-S128; Yang et al., J Pharmacol. Exp. Ther., 1997, 1247-1252). Therefore agonists of the BK-2 receptor may be useful in the treatment of Type II diabetes. Unterberg et al. (J Cereb. Blood Flow Metab., 1984, 574-585) report an increased permeability of the blood-brain barrier due to bradykinin. Thus, agonists of the BK-2 receptor could also be used to increase the brain levels of pharmaceutical compounds used to treat central nervous system disorders when administered with these compounds. Therefore, compounds that modulate the bradykinin B2 (BK-2) receptor as agonists or antagonists would have considerable therapeutic benefit.
A number of tissues and cultured cell lines has been assessed for the presence of bradykinin receptors using radiolabeled bradykinin or a radiolabeled bradykinin analogue as a probe (See Hall, Gen. Pharma., 1997, 28: 1-6, for a compilation of such studies.). Although bradykinin and its analogues exhibit high affinity for bradykinin receptors there are some difficulties in using these ligands as receptor localization probes. Bradykinin binds to both BK-1 and BK-2 receptors and therefore cannot be used to distinguish receptor subtypes. Also bradykinin and many of its peptide analogues are susceptible to rapid degradation by kininases, leading to experimental difficulties. Nonpeptidic ligands are not susceptible to kininase activity. Therefore, small molecules that bind with high affinity and high selectivity to BK-2 receptors are especially desirable tools for BK-2 localization studies.
This invention provides compounds of Formula I (shown below) and pharmaceutical compositions comprising compounds of Formula I. Preferred compounds of the invention exhibit high selectivity for G-coupled protein receptors, especially bradykinin B2 receptors. Preferred compounds of Formula I also bind with high affinity to these receptors.
The invention further provides methods of treating patients suffering from certain inflammatory disorders and other conditions mediated by bradykinin. The invention also provides methods of treating patients (humans and non-humans) suffering from conditions in which agonism of the BK-2 receptor may prove beneficial. Treatment of humans, domesticated companion animals (pets) or livestock animals suffering such conditions with art effective amount of a compound of the invention is contemplated by the invention.
In a separate aspect, the invention provides methods of using compounds of this invention as positive controls in assays for BK-2 receptor activity and using appropriately labeled compounds of the invention as probes for the localization of BK-2 receptors in tissue sections.
Accordingly, in one aspect, the invention is directed to compounds of Formula I: 
wherein:
R1 is not 3-fluorobenzyl and represents
(i) (C2-C6)alkenyl; or
(ii) R1 represents aryl(C1-C6)alkyl or heteroaryl(C1-C6)alkyl, where the ring portion of each is optionally substituted with one, two or three groups independently selected from halogen, nitro, trifluoromethyl, trifluoromethoxy, cyano, hydroxy, (C1-C6)alkyl, hydroxy(C1-C6)alkyl, amino, mono- or di(C1-C6)alkylamino, amino(C1-C6)alkyl, mono- or di(C1-C6)alkylamino(C1-C6)alkyl, mono- or di(C1-C6)alkylamino(C1-C6)alkoxy, or
(iii) OR7, O(CH2)nC(O)R7, O(CH2)nNR7R8, O(CH2)nCO2R7, NR7COR8, COR7, CONR7R8 or CO2R7 where
n=1, 2, 3, or 4 and
R7 and R8 are the same or different and represent hydrogen, SO2Me, or (C1-C6)alkyl; or
R7 and R8 together with the nitrogen to which they are attached form a 5, 6 or 7 membered carbocyclic ring where up to two of the members in the ring are optionally hetero atoms selected from oxygen, sulfur and nitrogen, and where each member is optionally substituted with (C1-C6)alkyl;
R2 represents
hydrogen, hydroxy, halogen, trifluoromethyl, trifluoromethoxy, amino(C1-C6)alkyl, mono- or di(C1-C6)alkylamino(C1-C6), mono- or di(C1-C6)alkylamino(C1-C6)alkoxy; or
OR7, O(CH2)nC(O)R7, O(CH2)nNR7R8, O(CH2)nCO2R7, NR7COR8, COR7, CONR7R8 or C02R7 where
n=1, 2, 3, or 4; and
R7 and R8 are the same or different and represent hydrogen, SO2Me, or (C1-C6)alkyl; or
R7 and R8 together with the nitrogen to which they are attached form a 5, 6 or 7 membered carbocyclic ring where up to two of the members are optionally hetero atoms selected from oxygen, sulfur and nitrogen, and where each member is optionally substituted with (C1-C6)alkyl;
R3 represents (C1-C6)alkyl;
R4 represents halogen or trifluoromethyl;
R5 and R6 are the same or different and represent hydrogen, trifluoromethyl, trifluoromethoxy, cyano, (C1-C6)alkyl, halogen, (C1-C6)alkylamino(C1-C6)alkyl, mono or di(C1-C6)alkylamino(C1-C6), or mono- or di(C1-C6)alkylamino(C1-C6)alkoxy; or
R4 and R5 together with the carbon atoms to which they are attached form a 5 or 6 membered aromatic ring which is optionally substituted with one or two groups independently selected from
halogen, nitro, trifluoromethyl, cyano, hydroxy, (C1-C6)alkyl, amino, or mono- or di(C1-C6)alkylamino; or
OR7, O(CH2)nC(O)R7, O(CH2)nNR7R8, O(CH2)nCO2R7, NR7COR8, COR7, CONR7R8 or CO2R7 where
n=1, 2, 3, or 4; and
R7 and R8 are the same or different and represent hydrogen, SO2Me, or (C1-C6)alkyl; or
R7 and R8 together with the nitrogen to which they are attached form a 5, 6 or 7 membered carbocyclic ring where up to two of the members are optionally hetero atoms selected from oxygen, sulfur and nitrogen, and where each member is optionally substituted with (C1-C6)alkyl;
X represents a bond or CH2, where the CH2 is optionally mono- or disubstituted with a (C1-C6)alkyl or (C1-C6)alkoxy; and
A, B, C and D are the same or different and represent CH or N with the proviso that not more than two of A, B, C and D represent N.
Preferred compounds of the inventions are modulators of G-coupled protein receptors, especially BK-2 receptors. These compounds are therefore useful in the diagnosis and treatment of renal diseases, heart failure, hypertension, Meniere""s disease, vaginal inflammation and pain, peripheral circulatory disorders, climacteric disturbance, retinochoroidal circulatroy disorders, myocardial ischemia, myocardial infarction, postmyocardial infarction syndrome, angina pectoris, restenosis after percutaneous transluminal coronary angioplasty, hepatitis, liver cirrhosis, pancreatitis, ileus, diabetes, diabetic complications, male infertility or glaucoma, or for the increase of permeability of blood-brain barrier, pain, asthma and rhinitis.
In another aspect, the invention provides methods for treating and/or preventing the above-listed disorders, which methods comprise administration to a patient in need thereof of an effective amount of a compound of Formula I.
In yet another aspect, the invention provides intermediates useful in the preparation of the compounds of Formula I.
The compounds encompassed by the instant invention are represented by general Formula I set forth above and include the pharmaceutically acceptable non-toxic salts thereof.
In addition, the present invention also encompasses compounds of Formula II 
wherein R1 is as defined above for Formula I; and
R3 is C3-C6 alkyl, preferably n-butyl, isoamyl, or n-pentyl;
R4 is chloro or fluoro; and
Ra and Rb independently represent hydrogen or C1-C6 alkoxy.
More preferred compounds of Formula II are where R1 is benzyl mono- or disubstituted on the ring portion with
(C1-C6)alkyl, halogen, nitro, trifluoromethyl, trifluoromethoxy, cyano, hydroxy, (C1-C6)alkyl, hydroxy(C1-C6)alkyl, amino, mono- or di(C1-C6)alkylamino, aminomethyl, mono- or di(C1-C6)alkylamino(C1-C6)alkyl, or mono- or di(C1-C6)alkylamino(C1-C6)alkoxy; or
OR7, O(CH2)nC(O)R7, O(CH2)nNR7R8, O(CH2)nCO2R7, NR7COR8, COR7, CONR7R8 or CO2R7 where
n=1, 2, 3, or 4; and
R7 and R8 are the same or different and represent hydrogen, SO2Me, or (C1-C6)alkyl; or
R7 and R8 together with the nitrogen to which they are attached form a 5, 6 or 7 membered carbocyclic ring where up to two of the members are optionally hetero atoms selected from oxygen, sulfur and nitrogen, and where each member is optionally substituted with (C1-C6)alkyl;
except that R1 is not 3-fluorobenzyl.
Even more preferred compounds of Formula II are those where R4 is chloro and Ra and Rb are independently C1-C6 alkoxy, most preferably C1-C3 alkoxy. Particularly preferred compounds of Formula II are those where R3 is butyl or isoamyl, i.e, 3-methylbutyl, R4 is chloro, and Ra and Rb are independently C1-C2 alkoxy, most preferably methoxy.
In addition, the present invention encompasses compounds of the Formula III. 
wherein R1 is as defined above for Formula I; and
R3 is C3 or C6 alkyl, preferably n-butyl, isoamyl, or n-pentyl;
R4 is chloro or fluoro; and
Ra and Rb independently represent hydrogen or C1-C6 alkoxy.
More preferred compounds of Formula II are where R1 is benzyl mono- or disubstituted on the ring portion with
(C1-C6)alkyl, halogen, nitro, trifluoromethyl, trifluoromethoxy, cyano, hydroxy, (C1-C6)alkyl, hydroxy(C1-C6)alkyl, amino, mono- or di(C1-C6)alkylamino, aminomethyl, mono- or di(C1-C6)alkylamino(C1-C6)alkyl, or mono- or di(C1-C6)alkylamino(C1-C6)alkoxy; or
OR7, O(CH2)nC(O)R7, O(CH2)nNR7R8, O(CH2)nCO2R7, NR7COR8, COR7, CONR7R8 or CO2R7 where
n=1, 2, 3, or 4; and
R7 and R8 are the same or different and represent hydrogen, SO2Me, or (C1-C6)alkyl; or
R7 and R8 together with the nitrogen to which they are attached form a 5, 6 or 7 membered carbocyclic ring where up to two of the members are optionally hetero atoms selected from oxygen, sulfur and nitrogen, and where each member is optionally substituted with (C1-C6)alkyl;
except that R1 is not 3-fluorobenzyl.
Even more preferred compounds of Formula III are those where R4 is chloro and Ra and Rb are independently C1-C6 alkoxy, most preferably C1-C3 alkoxy. Particularly preferred compounds of Formula III are those where R3 is butyl or isoamyl, i.e, 3-methylbutyl, R4 is chloro, and Ra and Rb are methoxy.
Particularly preferred R1 groups in Formulae II and III are benzyl substituted in the 2- or 3-positions of its phenyl ring with hydroxy, C1-C2 alkyl, C1-C2 alkoxy, xcfx89-[4-((C1-C6)alkyl)piperazinyl] (C1-C4)alkoxy, methyl sulfonate, 3-halopropoxy, carboxymethoxy, 2-, 3-, or 4-pyridyl(C1-C6)alkyl, preferably 2-, 3-, or 4-pyridyl(C1-C2)alkyl, 3-pyrrolidinyl(C1-C6)alkoxy; tetrazolyl, halogen, preferably bromo, fluoro or chloro, alkylamino(C1-C6)alkoxy, preferably 3-(methylamino)propoxy or 2-(ethylamino)ethoxy, morpholinyl(C1-C6) alkoxy, preferably 3-morpholin-4-ylpropoxy or 2-(morpholin-4-yl)ethoxy, xcfx89-piperidyl(C1-C4)alkoxy, (C1-C3)alkoxycarbonylmethoxy, trifluoromethyl, (N-(methylsulfonyl) carbamoyl)methoxy, and nitro.
The most preferred among these 2- or 3-substituted benzyl groups are those substituted in the 2-position of the phenyl. ring.
Other particularly preferred R1 groups of the invention are 2-fluoro-, 2-bromo- or 2-chloro-5-nitrobenzyl, 3,5-dihalobenzyl where the halogen is chloro or fluoro, 5-hydroxy(C1-C2)alkyl-2-(C1-C3)alkoxybenzyl, 5-(C2-C4)alkanoyl-2-(C1-C3)alkoxybenzyl, and 3-amino-5- or 6-(C1-C2)alkoxybenzyl.
Still other preferred R1 groups include alkenyl groups such as allyl or 1-buten-2- or 3-yl.
Other particularly preferred R1 groups include 2- or 3-pyridyl.
By xcfx89-substitution as used herein is meant the terminal position on, for example, an alkyl chain. Examples of such groups are 3-hydroxypropyl, 5-morpholin-4-ylpentyl, 3-piperazinylpropoxy, and 4-methoxybutyl.
By xe2x80x9calkylxe2x80x9d, xe2x80x9clower alkylxe2x80x9d, and xe2x80x9c(C1-C6)alkylxe2x80x9d in the present invention is meant straight or branched chain alkyl groups having 1-6 carbon atoms, such as, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, 2-pentyl, isopentyl, neopentyl, hexyl, 2-hexyl, 3-hexyl, and 3-methylpentyl.
By xe2x80x9calkoxyxe2x80x9d, xe2x80x9clower alkoxyxe2x80x9d, and xe2x80x9c(C1-C6)alkoxyxe2x80x9d in the present invention is meant straight or branched chain alkoxy groups having 1-6 carbon atoms, such as, for example, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, pentoxy, 2-pentoxy, isopentoxy, neopentoxy, hexoxy, 2-hexoxy, 3-hexoxy, and 3-methylpentoxy.
By the term xe2x80x9chalogenxe2x80x9d in the present invention is meant fluorine, bromine, chlorine, and iodine.
By the term xe2x80x9cpatientxe2x80x9d is meant human patients as well as domestic companion animals (pets) and livestock animals.
By xe2x80x9cheteroarylxe2x80x9d is meant one or more aromatic ring systems of 5-, 6-, or 7-membered rings containing at least one and up to four heteroatoms selected from nitrogen, oxygen, or sulfur. Such heteroaryl groups include, for example, thienyl, furanyl, thiazolyl, imidazolyl, (is)oxazolyl, pyridyl, pyrimidinyl, (iso)quinolinyl, napthyridinyl, benzimidazolyl, benzoxazolyl. Preferred heteroaryls are thiazolyl and pyridyl.
By xe2x80x9carylxe2x80x9d is meant an aromatic carbocyclic group having a single ring (e.g., phenyl), multiple rings (e.g., biphenyl), or multiple condensed rings in which at least one is aromatic, (e.g., 1,2,3,4-tetrahydronaphthyl, naphthyl, anthryl, or phenanthryl), which is optionally mono-, di-, or trisubstituted with, e.g., halogen, lower alkyl, lower alkoxy, lower alkylthio, trifluoromethyl, lower acyloxy, aryl, heteroaryl, and hydroxy. A preferred aryl is phenyl.
Preferred (C1-C6)alkylamino groups are methylamino and ethylamino; preferred di(C1-C6)alkylamino groups are diethylamino and dimethylamino; preferred amino(C1-C6)alkyl groups are aminomethyl and 2-aminoethyl; preferred mono- and di(C1-C6)alkylamino(C1-C6)alkyl groups are methylaminomethyl, dimethylaminomethyl, ethylaminomethyl; and 2-(ethylamino)ethyl.
Representative compounds of the invention are shown below in Table 1.
In certain situations, the compounds of Formula I may contain one or more asymmetric carbon atoms, so that the compounds can exist in different stereoisomeric forms. These compounds can be, for example, racemates or optically active forms. In these situations, the single enantiomers, i.e., optically active forms, can be obtained by asymmetric synthesis or by resolution of the racemates. Resolution of the racemates can be accomplished, for example, by conventional methods such as crystallization in the presence of a resolving agent, or chromatography, using, for example a chiral HPLC column.
Representative compounds of the present invention, which are encompassed by Formula I, include, but are not limited to the compounds described in the Examples and their pharmaceutically acceptable acid addition salts. In addition, if the compound of the invention is obtained as an acid addition salt, the free base can be obtained by basifying a solution of the acid salt. Conversely, if the product is a free base, an addition salt, particularly a pharmaceutically acceptable addition salt, may be produced by dissolving the free base in a suitable organic solvent and treating the solution with an acid, in accordance with conventional procedures for preparing acid addition salts from base compounds.
Non-toxic pharmaceutical salts include salts of acids such as hydrochloric, phosphoric, hydrobromic, sulfuric, sulfinic, formic, toluenesulfonic, methanesulfonic, nitric, benzoic, citric, tartaric, maleic, hydroiodic, alkanoic such as acetic, HOOCxe2x80x94(CH2)nxe2x80x94COOH where n is 0-4, and the like. Those skilled in the art will recognize a wide variety of non-toxic pharmaceutically acceptable addition salts.
The present invention also encompasses the acylated prodrugs of the compounds of Formula I. Those skilled in the art will recognize various synthetic methodologies which may be employed to prepare non-toxic pharmaceutically acceptable addition salts and acylated prodrugs of the compounds encompassed by Formula I.
Selective agonists or antagonists of the bradykinin B2 receptor provide compounds useful in treatment of renal diseases, heart failure, hypertension, Meniere""s disease, vaginal inflammation and pain, peripheral circulatory disorders, climacteric disturbance, retinochoroidal circulatroy disorders, myocardial ischemia, myocardial infarction, postmyocardial infarction syndrome, angina pectoris, restenosis after percutaneous transluminal coronary angioplasty, hepatitis, liver cirrhosis, pancreatitis, ileus, diabetes, diabetic complications, male infertility or glaucoma, or for the increase of permeability of blood-brain barrier, pain, asthma, rhinitis. The invention provides methods of treating patients suffering from such disorders with an amount of a compound of the invention sufficient to reduce the symptoms of the disorder.
Bradykinin has been shown to increase the permeability of blood-brain barrier and blood-brain tumor barrier. The invention provides a method of increasing the brain concentration of a CNS active compound which comprises administering to a patient in need of such treatment a compound of the invention, that is a selective agonist of the BK-2 receptor, along with a CNS active compound, and thereby increasing the brain concentration of the CNS active compound. In a particularly preferred embodiment the invention provides a method of increasing the brain concentration of anti-cancer and anti-tumor agents which comprises administering a patient suffering from brain cancer or a brain tumor a compound of the invention that is a selective agonist of the BK-2 receptor, along with an anti-cancer and anti-tumor agent, and thereby increasing the brain concentration of the anti-cancer or anti-tumor agent.
The compounds of general Formula I may be administered orally, topically, parenterally, by inhalation or spray or rectally in dosage unit formulations containing conventional non-toxic pharmaceutically acceptable carriers, adjuvants and vehicles. The term parenteral as used herein includes subcutaneous injections, intravenous, intramuscular, intrasternal injection or infusion techniques. In addition, there is provided a pharmaceutical formulation comprising a compound of general Formula I and a pharmaceutically acceptable carrier. One or more compounds of general Formula I may be present in association with one or more non-toxic pharmaceutically acceptable carriers and/or diluents and/or adjuvants and if desired other active ingredients. The pharmaceutical compositions containing compounds of general Formula I may be in a form suitable for oral use, for example, as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules, emulsion, hard or soft capsules, or syrups or elixirs.
Compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions may contain one or more agents selected from the group consisting of sweetening agents, flavoring agents, coloring agents and preserving agents in order to provide pharmaceutically elegant and palatable preparations. Tablets contain the active ingredient in admixture with non-toxic pharmaceutically acceptable excipients which are suitable for the manufacture of tablets. These excipients may be for example, inert diluents, such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example, corn starch, or alginic acid; binding agents, for example starch, gelatin or acacia, and lubricating agents, for example magnesium stearate, stearic acid or talc. The tablets may be uncoated or they may be coated by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a time delay material such as glyceryl monosterate or glyceryl distearate may be employed.
Formulations for oral use may also be presented as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or kaolin, or as soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium, for example peanut oil, liquid paraffin or olive oil.
Aqueous suspensions contain the active materials in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients are suspending agents, for example sodium carboxymethylcellulose, methylcellulose, hydropropylmethylcellulose, sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia; dispersing or wetting agents may be a naturally-occurring phosphatide, for example, lecithin, or condensation products of an alkylene oxide with fatty acids, for example polyoxyethylene stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols, for example heptadecaethyleneoxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitol such as polyoxyethylene sorbitol monooleate, or condensation products of ethylene oxide with partial esters derived from fatty acids and hexitol anhydrides, for example polyethylene sorbitan monooleate. The aqueous suspensions may also contain one or more preservatives, for example ethyl, or n-propyl p-hydroxybenzoate, one or more coloring agents, one or more flavoring agents, and one or more sweetening agents, such as sucrose or saccharin.
Oily suspensions may be formulated by suspending the active ingredients in a vegetable oil, for example arachis oil, olive oil, sesame oil or coconut oil, or in a mineral oil such as liquid paraffin. The oily suspensions may contain a thickening agent, for example beeswax, hard paraffin or cetyl alcohol. Sweetening agents such as those set forth above, and flavoring agents may be added to provide palatable oral preparations. These compositions may be preserved by the addition of an anti-oxidant such as ascorbic acid.
Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water provide the active ingredient in admixture with a dispersing or wetting agent, suspending agent and one or more preservatives. Suitable dispersing or wetting agents and suspending agents are exemplified by those already mentioned above. Additional excipients, for example sweetening, flavoring and coloring agents, may also be present.
Pharmaceutical compositions of the invention may also be in the form of oil-in-water emulsions. The oily phase may be a vegetable oil, for example olive oil or arachis oil, or a mineral oil, for example liquid paraffin or mixtures of these. Suitable emulsifying agents may be naturally-occurring gums, for example gum acacia or gum tragacanth, naturally-occurring phosphatides, for example soy bean, lecithin, and esters or partial esters derived from fatty acids and hexitol, anhydrides, for example sorbitan monoleate, and condensation products of the said partial esters with ethylene oxide, for example polyoxyethylene sorbitan monoleate. The emulsions may also contain sweetening and flavoring agents.
Syrups and elixirs may be formulated with sweetening agents, for example glycerol, propylene glycol, sorbitol or sucrose. Such formulations may also contain a demulcent, a preservative and flavoring and coloring agents. The pharmaceutical compositions may be in the form of a sterile injectable aqueous or oleaginous suspension. This suspension may be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents which have been mentioned above. The sterile injectable preparation may also be sterile injectable solution or suspension in a non-toxic parentally acceptable diluent or solvent, for example as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer""s solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose any bland fixed oil may be employed including synthetic mono-or diglycerides. In addition, fatty acids such as oleic acid find use in the preparation of injectables.
The compounds of general Formula I may also be administered in the form of suppositories for rectal administration of the drug. These compositions can be prepared by mixing the drug with a suitable non-irritating excipient which is solid at ordinary temperatures but liquid at the rectal temperature and will therefore melt in the rectum to release the drug. Such materials are cocoa butter and polyethylene glycols.
Compounds of general Formula I may be administered parenterally in a sterile medium. The drug, depending on the vehicle and concentration used, can either be suspended or dissolved in the vehicle. Advantageously, adjuvants such as local anesthetics, preservatives and buffering agents can be dissolved in the vehicle.
Dosage levels of the order of from about 0.1 mg to about 140 mg per kilogram of body weight per day are useful in the treatment of the above-indicated conditions (about 0.5 mg to about 7 g per patient per day). The amount of active ingredient that may be combined with the carrier materials to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. Dosage unit forms will generally contain between from about 1 mg to about 500 mg of an active ingredient.
Frequency of dosage may also vary depending on the compound used and the particular disease treated. However, for treatment of most disorders, a dosage regimen of 4 times daily or less is preferred. For the treatment of chronic conditions, a dosage regimen of 1 or 2 times daily is particularly preferred. For the treatment of acute disorders, a single dose that rapidly reaches effective concentrations is desirable.
It will be understood, however, that the specific dose level for any particular patient will depend upon a variety of factors including the activity of the specific compound employed, the age, body weight, general health, sex, diet, time of administration, route of administration, and rate of excretion, drug combination and the severity of the particular disease undergoing therapy.
Preferred compounds of the invention will have certain pharmacological properties. Such properties include, but are not limited to oral bioavailability, low toxicity, low serum protein binding and desirable in vitro and in vivo half-lifes. Penetration of the blood brain barrier for compounds used to treat CNS disorders is necessary, while low brain levels of compounds used to treat periphereal disorders are often preferred.
Assays may be used to predict these desirable pharmacological properties. Assays used to predict bioavailability include transport across human intestinal cell monolayers, including Caco-2 cell monolayers. Toxicity to cultured hepatocyctes may be used to predict compound toxicity. Penetration of the blood brain barrier of a compound in humans may be predicted from the brain levels of the compound in laboratory animals given the compound intravenously.
Serum protein binding may be predicted from albumin binding assays. Such assays are described in a review by Oravcovxc3xa1, et al. (Journal of Chromatography B (1996) volume 677, pages 1-27).
Compound half-life is inversely proportional to the frequency of dosage of a compound. In vitro half-lifes of compounds may be predicted from assays of microsomal half-life as described by Kuhnz and Gieschen (Drug Metabolism and Disposition, (1998) volume 26, pages 1120-1127).
The present invention also pertains to packaged pharmaceutical compositions for treating disorders responsive to BK-2 receptor modulation, e.g., treatment asthma, pain or rhinitis by BK-2 receptor modulation. The packaged pharmaceutical compositions include a container holding a therapeutically effective amount of at least one BK-2 receptor modulator as described supra and instructions for using the treating disorder responsive to BK-2 receptor modulation in the patient.
The present invention also pertains to methods of inhibiting the binding of bradykinin to the BK-2 receptor which methods involve contacting a compound of the invention with cells expressing BK-2 receptors, wherein the compound is present at a concentration sufficient to inhibit bradykinin binding to cells expressing a cloned human Bradykinin receptor in vitro and to methods for altering the signal-tranducing activity of BK-2 receptors, said method comprising exposing cells expressing such receptor to an effective amount of a compound of the invention.
The invention furthermore provides methods of using compounds of this invention as positive controls in assays for receptor activity and using appropriately labeled compounds of the invention as probes for the localization of receptors, particularly BK-2 receptors, in tissue sections. Such probes are useful for in vitro studies, such as binding assays and autoradiography of tissue sections and for in vivo techniques such as PET and SPECT scans.
Compounds of the invention can be prepared using the reactions depicted in Schemes I to VII. In Schemes I-VII, the groups R1, R3, R7, R8 and X are as defined in general Formula I. The numbers appearing below or adjacent the chemical structures in these schemes refer to intermediates and are not to be confused with the compound numbers found in the examples. 
Those having skill in the art will recognize that the starting materials may be varied and additional steps employed to produce compounds encompassed by the present invention, as demonstrated by the following examples.
The disclosures of all articles and references mentioned in this application, including patents, are incorporated herein by reference.
The invention is illustrated further by the following examples which are not to be construed as limiting the invention in scope or spirit to the specific procedures described in them.
The starting materials and various intermediates may be obtained from commercial sources, prepared from commercially available organic compounds, or prepared using well known synthetic methods.